Não informado. (1946). Iowa farm science. Iowa State University of Science and Technology, Cooperative Extension Service.
Chicago-viite (17. p.)Não informado. Iowa Farm Science. Ames, Iowa: Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
MLA-viite (8. p.)Não informado. Iowa Farm Science. Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.